The present invention relates to filler neck caps, and particularly to a rotatable cap for closing the open mouth of a filler neck. More particularly, the present invention relates to a filler neck closure cap designed to indicate to the user the minimum acceptable closure torque to effect a sealed position in a filler neck.
Conventional caps for closing the filler neck of a vehicle fuel tank typically include a closure member carrying a seal for closing and sealing the mouth of the filler neck and a handle for turning the closure member to mount the closure member and seal in the filler neck. A typical filler neck cap includes a ring-shaped seal made of a resilient gasket material that is compressed between the cap and a filler neck receiving the cap to establish a sealed connection between the cap and the filler neck when the cap is mounted on the filler neck.
Frequent over-tightening of a filler neck fuel cap can crush or otherwise damage the O-ring gasket which provides the seal between the cap and the filler neck. A torque-control mechanism was developed to limit positively the amount of torque which could be applied by a user in the cap-advancing direction as the user rotates the cap on the filler neck to its fully seated filler neck-closing position thereon. Thus, a torque-control mechanism helps minimize wear and tear on the O-ring gasket and preserves the sealing capability of the gasket. See, for example, U.S. Pat. Nos. 4,913,303 to Harris, 4,083,209 to Sloan, Jr., and 5,110,003 to MacWilliams and International (PCT) Publication No. WO 00/20292 (published Apr. 13, 2000) to Harris, the disclosures of which are hereby incorporated by reference herein.
In recent applications, however, a more pervasive problem is cap under-tightening, that is, failure of users to tighten the cap to a properly torqued installed position on a filler neck. A filler neck cap in accordance with the present disclosure is made to address the under-tightening problem.
According to the present disclosure, a filler neck cap includes an axially outer portion rotatable about an axis of rotation, an axially inner portion adapted to close the filler neck, and a torque-limit signaler coupled to the axially outer and inner portions. The torque-limit signaler is configured to provide an audible and/or tactile and/or other receivable signal to a user (as the user is rotating a cap in a cap-advancing direction to its installed position within a tank filler neck) so that the user will be made aware that the cap has been xe2x80x9ctorquedxe2x80x9d or xe2x80x9ctightenedxe2x80x9d to an acceptable limit and has been installed properly within the filler neck. Once the user senses the signal produced by the torque-limit signaler, the user will know not to rotate the cap further in the cap-advancing direction and the cap therefore will be left in a properly torqued or tightened position within the filler neck.
In illustrative embodiments, the axially inner portion includes a closure base and an O-ring seal around the closure base. The axially outer portion includes a rotatable handle and a rotatable torque-transmission member positioned to lie between the handle and the closure base. The torque-limit signaler includes four xe2x80x9cunitsxe2x80x9d located between the torque-transmission member and the closure base. Each of these signaler units includes several lugs and notches on the underside of the torque-transmission member and a flexible spring arm cantilevered to one interior edge of a radially extending annular flange coupled to the closure base. The flexible spring arm extends into a lost-motion signal slot formed in the radially extending annular flange and carries a spring head that is movable on the flexible spring arm in axially up and down directions to xe2x80x9cinteractxe2x80x9d with the lugs and notches on the underside of the torque-transmission member.
A torque-limit signal is produced by the interaction between the spring head and its companion lugs and notches at a certain stage during rotation of the handle in a cap-advancing direction to install the cap in a filler neck. This torque-limit signal alerts a person rotating the handle about the axis of rotation in the cap-advancing direction that the cap has been torqued or tightened to an acceptable limit and the closure base has been installed properly within the filler neck. For example, as the person is rotating the handle in the cap-advancing direction, a spring head (carried on a flexible spring arm) will slip downwardly out of a drive notch located between first and second lugs to allow lost-motion movement of the torque-transmission member relative to the closure base through a predetermined acute angle to cause torque transmission from the torque-transmission member to the closure base to be interrupted temporarily. As a result of this temporary interruption, the closure base will not rotate about the axis of rotation in response to continued rotation of the handle and the torque-transmission member in the cap-advancing direction through a small angle of about 10xc2x0.
An audible noise and/or a tactile sensation associated with such interaction of the spring head carried on the flexible spring arm and the lugs and notches on the underside of the torque-transmission member provided to the person rotating the handle during temporary interruption of torque transmission from the torque-transmission member to the closure base will be the xe2x80x9csignalxe2x80x9d that the closure has been torqued or tightened sufficiently and that rotation of the handle in the cap-advancing direction is not causing the closure to rotate further in the filler neck. Once the person has rotated the handle and the torque-transmission member through that small lost-motion angle relative to the closure base, one of the lugs coupled to the underside of the torque-transmission member and arranged to extend into the lost-motion signal slot formed in the radially extending annular flange will contact an edge of the lost-motion signal slot to reestablish the driving (i.e., torque-transmitting) connection between the torque-transmission member and the closure base in the filler neck.
Additional features of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.